The Hogwarts Mystery
by iron-holmes
Summary: Sherlock and the gang are attending Hogwarts. Find out how Sherlock deals with Malfoy, The Dark Lord as well as Moriarty! Follow Sherlock, Harry and everyone else on mysteries around the old walls of Hogwarts. Maybe some Sherlock or other character/OC
1. Chapter 1

**So here is some Potter!lock for you all! Now I'm explaining this now, Harry Potter and everyone else still exists here. They are in the same year with Sherlock but (for example) in the books, Harry was the youngest Quidditch player, now it's Sherlock. But it's not like that everywhere. Like Sherlock solves the mysteries, explains them to Harry which helps Harry fight the Dark Lord (no I'm not saying his name). Let's crack on then. **

Mycroft Holmes always had a plan. Always. As he dragged his younger brother towards King's Cross station, he realized his plan was failing miserably. Never had he thought that his younger brother would decline going to the school of Witchcraft and Wizardry. The boy was brilliant at magic! He was quite brilliant at everything, but Mycroft Holmes would never admit that. Now, he had to suffer through everything passing through his younger brother's mind after he had agreed to go to the school. Of course, mother and father would never take no for an answer, especially from the reckless, trouble making boy but they wouldn't want to break his spirit by forcing him to go. So they had their eldest son manipulate the boy into going.

Sherlock Holmes huffed as he finished explaining the life stories of every incompetent Muggle passing by them. The only reason he had agreed to go to Hogwarts was because, in a way he wouldn't admit, he owed Mycroft. His brother had taught him how to deduce people properly. It's not like he wasn't able to. He just wasn't able to formulate an answer through all the facts he was observing. But Mycroft had taught him a great talent, one in which he excelled in, better than Mycroft himself! Instead of stuffing his face with treacle tart like _some people_, Sherlock focused on his magic, his deductions and everything else he deemed useful. One activity in particular (it irked Mycroft, which made it even better) was Quidditch. Sherlock was somehow drawn to the game because of it's quick thinking strategies. If you weren't quick witted, you lost. When Sherlock got his first broomstick, the Nimbus 1700, he was over the moon, quite literally as he flew over the moon and back to their mansion.

"Now Sherlock, remember, Quidditch is only for second years. You will only be learning to fly this year so please, just try not to show off" Mycroft said sternly. Sherlock nodded but didn't seem to be listening. Mycroft sighed and kept pushing his own cart with his trunk and owl, always keeping a keen eye on his younger brother. Who knows where the boy can scamper off to when he's not being watched. At 11 years old, Sherlock Holmes can either act more mature than the wisest of men or more immature than a toddler. But Mycroft had noted that his younger brother had become more self aware of the others around him. He has learned, like any other Holmes, that caring is not an advantage. He was a sociopath, and a high functioning one that is. Mycroft almost pitied his younger brother as he got strange looks from other children when he walked around the neighborhood. One thing Mycroft Holmes did not understand was how at times people could be ignorant of a young lad, dressed in black, with dark, shaggy curls and porcelain white skin, walking about on his own in the shadows of town. But other times, watch him like a hawk because he stands out for being alone a somewhat creepy, as the Muggles would say. People decide to pay attention when attention is unwanted. When attention is wanted, they don't show it. But why?

"I'm a show off that's what we do!" Sherlock exclaimed as they walked past various platforms.

"Not unless you actually have _someone_ to show off to" Mycroft stated. The boy glared at him, opening his mouth for a rather nasty insult but closing it again. Mycroft would probably tell mummy and she wouldn't let him play Quidditch anymore. Mycroft smiled smugly at his younger brother before stopping him between platform 9 and 10.

"Right then. There are separate carriages for the prefects, so you shall be going on your own. Do you think you can manage without causing a commotion?" Mycroft asked.

"I'll be fine, Mycroft" Sherlock spat.

"And what of the ones surrounding you? Will they be fine as well?" Mycroft asked, hinting Sherlock is absolutely _not_ allowed to turn anyone into toads. Or worse.

Sherlock glared at his older brother before pushing past him and charging towards the wall with his trunk as well as the cage that held his black cat. He sunk into the bricks and emerged on the other side. On the side of the Wizarding World. Mycroft emerged right after him, pushing his cart towards his prefect buddies. He would have to embarrass Mycroft some other time. He ignored all of the people around him, with their hugging and crying because their children were leaving. Uh, sentiment!

Sherlock sat in his cabin, alone, flicking his wand, and changing the color of the kitten from coal black to red to yellow and so on. The cat meowed from it's seat on the opposite bench. There was a knock on the door and Sherlock quickly changed the kitten back to black before anyone caught an under-aged wizard using magic.

"Excuse me, do you mind? Everywhere else if full" Said a sandy haired boy, a bit short. Sherlock quickly scanned him: slight limp, probably broken ankle, hasn't slept in days, so the ankle must be hurting enough to disturb sleep, how did he break his ankle? Holds himself quite neatly, cropped haired, clean jumper, jeans, loafers, not rich but not entirely poor, well mannered considering he asked Sherlock's permission to come in.

"Not at all" Sherlock replied, putting on a fake smile. The boy tucked an owl cage in the small compartment and sat down near the kitten, who jumped into Sherlock's lap.

"I'm John, by the way. John Watson" He said, stretching out a slightly tanned hand.

"Sherlock Holmes" Sherlock stated, quickly shaking his hand before recoiling in his seat while the kitten jumped off his lamp and curled up on the seat next to him.

"Are you from _the_ Holmes family!?" John asked.

"Um yes" Sherlock said a bit awkwardly. There weren't that many Holmes in England.

"All I heard in Diagon Alley is _Holmes_ and _Harry Potter_" John explained. Well his family was famous. They were one of the richest pureblood families in the wizard world.

"Who's that?" John asked suddenly, pointing at the furry creature.

"Thanatos" Sherlock said, scratching the kitten behind the ears.

"Like the Greek god?" John asked. So he was partially intelligent.

"Minor Greek god. Thanatos it the god of peaceful or torturous death" Sherlock explained.

"You named your cat, after...death? Why" John asked.

"Why not?" Sherlock asked. He studied John and noted his expression: surprise.

"How's your ankle?" Sherlock asked suddenly.

"What? How did you-" John began but Sherlock cut him off.

"You were limping slightly when you walked in. Also the fact that you place your injured foot over the other, not wanting to put weight on it. As well as the fact that you haven't slept in a while, which is from the pain of the injury not the stress of going to a school full of wizards after you've only found out your a wizard" Sherlock explained all too quickly.

"How did you know?" John asked.

"I don't know. I notice" Sherlock stated.

"That was brilliant. Absolutely amazing!" John suddenly exclaimed. Sherlock stared at him. Nobody has ever complimented him on his deductions. He usually got beat up. Actually, he never got beat up because he was reckless enough to fight back.

"You think so?" Sherlock asked quietly.

"Of course I do. That was fantastic!" John concluded.

"That's not what people normally say" Sherlock said.

"What do people normally say?" John asked.

"Piss off" Sherlock answered. John looked at Sherlock with a concerned expression but it vanished as soon as they broke into grins.

"How did you know I just found out I'm a wizard" John asked.

"You were staring before you walked in while I was changing Thanatos to different colors" Sherlock stated.

"Wow" John said.

"What about your owl. What's her name?" Sherlock asked, glancing at the barn owl above them. Barn owl, typical, he couldn't afford better.

"How did you know it was a her? You know what, never mind. Her name is Tea" John said proudly. Sherlock cocked an eyebrow. He might have to rethink the partial intelligence that this boy showed because he clearly lacked creativity.

"Why Tea?" Sherlock asked, clearly curious at the unimaginative name.

"Because she's the color of the tea that my mum makes" John stated. Sherlock smiled lightly at the small joke before turning his attention towards the landscape, passing by in a blur of greens and blues.

"What kind of wand is that?" John asked, pointing at the wooden stick Sherlock was fiddling with.

"Holly wood. 12''. Dragon Heartstring" Sherlock stated. He remembered how he had caused chaos at Ollivander's when he was picking his wand. But this one had picked him.

"Cool" John said. Sherlock glanced at the wooden stick poking out of John's pocket. Dark wood, must be an elm. About 10'', judging by how deep it goes into his pocket. Has a silver glint to it, unicorn hair then. Sherlock turned his attention back out the window.

He had probably been staring out the window for a few hours because next time he was aware of his surroundings, he heard the wheels of the tea trolley coming their way. There was a knock on the door and plump lady pushing a cart filled with different types of sweets stood there, smiling kindly at them.

"Hungry dears?" She asked. John was staring at all the candy while Sherlock merely rolled his eyes, pulling out his pouch a gold Galleon and a few silver Sickles. He handed them to the woman and plucked a few Chocolate Frogs from the cart.

"Enjoy!" She called before walking down the corridor to the next cabin.

"What's that?" John asked, looking at the green packets with wide eyes. Sherlock handed him one without replying.

"Don't let them get away" Sherlock warned as he opened the packet and quickly caught the frog as it jumped out. It stilled at his touch and turned into chocolate. John cautiously opened his own, catching the frog before it jumped away. He grinned as it turned to chocolate and took a bite out of it. Sherlock glanced at the card on the back as he ate his own Chocolate Frog: Dumbledore. Obviously, the old bloke was on all the cards. He winked at Sherlock before disappearing.

They ate the rest of the Chocolate Frogs before John fell asleep. Sherlock blocked everything out, slipping into his Mind Palace. He would do something productive till it was time to change into their robes before they arrived at Hogwarts School of Witchcraft and Wizardry.

**Sherlock will be meeting Harry and the gang! Everyone will be interacting with everyone, just like in the books! **


	2. Chapter 2

**I'm trying to Balance out 3 stories at a time so don't hate me if I may not update here!**

The first years went up the stone steps to greet Professor Mcgonagall. Unfortunately, Sherlock was already immensely bored. The castle was just as he had expected, old, a bit mysterious and frankly cold. Well no wonder, the bloody place is over 1000 years old! Sherlock seemed to have taken some kind of liking to John because he didn't dismiss him as the sandy haired boy stayed close to Sherlock. As Sherlock leaned against the banister while the first years filed in in front of the Professor, John stayed close, staring in amazement at everything around him.

"Welcome to Hogwarts. Now, in a few moments, you will pass through these doors and join your classmates. But before you can take your seats you must be sorted into your houses. They are Gryffindor, Ravenclaw, Hufflepuff, and Slytherin. Now, while you are here, your house will be like your family. Your triumphs will earn you house points. Any rule breaking, and you will lose points. At the end of the year, the house with the most points is awarded the house cup!" Professor Mcgonagall announced as soon as the chatter had died down. Just as she finished her speech, a boy with chubby cheeks and by Sherlock's description, a stupid expression, jumped to her feet.

"Trevor!" He exclaimed, picking a brown toad from the top step. As soon as Mcgonagall looked down at him, snickering broke out in the hall. Sherlock managed a smile. It always amazed him how incompetent ordinary people were! He heard the boy mumble apologies before disappearing in the crowd of first years.

"The sorting ceremony will begin momentarily" Professor Mcgonagall said before exiting into the Great Hall.

"So it's true then, what they're saying on the train. Another Holmes has come to Hogwarts" said a boy with slicked back, nearly white hair to Sherlock. Many whispers broke out among the first years. He quickly analyzed the boy. Rich, definitely, over confident, most likely gay with that level of grooming, wants power like most pure blood families, Slytherin.

"I'm Malfoy. Draco Malfoy" He said, holding out a hand for Sherlock to shake.

"Sherlock Holmes" Sherlock introduced, quickly shaking Malfoy's hand before stuffing it back into the pocket of his robes.

"And you are?" He asked John distastefully.

"John Watson" John said, smiling and shaking Malfoy's hand. Malfoy gave him a weak smile before turning to a shaggy haired boy with round glasses. Sherlock tuned out as soon as Malfoy opened his mouth to speak to the boy. John nudged Sherlock as soon as Professor Mcgonagall returned.

"We're ready for you now" She said as she led them out into the Great Hall. Sherlock walked by John, trying to ignore the looks his older brother was giving him from the Slytherin table.

"It's not real, the ceiling. It's just bewitched to look like the night sky. I read about it in _Hogwarts: A History_" Said a girl somewhere in front of Sherlock. So someone is partially intelligent here! He'll have to try and not insult her.

Mcgonagall led them to the front of the room, in front of the long table where all the teachers sat. Sherlock observed all of them but found the results quite boring. Ordinary teachers.

"I have a few start of term notices I wish to announce. The first years please note that the dark forest is strictly forbidden to all students. Also, our caretaker, Mr. Filch has asked me to remind you that the 3rd floor corridor on the right hand side is out of bounds to everyone who does not wish to die a most painful death. Thank you" Dumbledore announced. Why was the 3rd corridor on the right hand side out of bounds? Sherlock would have to manipulate John to go and investigate with him.

"When I call your name, you will come forth, I shall place the sorting hat on your head, and you will be sorted into your houses" Mcgonagall said as she pulled out a scroll. She began reading names and first years came up, sitting on the stool and being sorted into houses.

"Are you nervous?" John whispered.

"No" Sherlock replied flatly. John nodded just as they called his name.

"Gryffindor!" The hat exclaimed as soon as it touched John's sandy hair. The next name to be called was Sherlock's. Whispers broke out across the entire hall as he walked up the 3 steps and sat down on the wooden stool. The heavy, old hat was lowered onto his head, pressing his curls into his eyes.

"Hmm...difficult, very difficult. Plenty of courage I see, not a bad mind, either. There's talent, oh yes. But where to put you?" The hat thought.

"No not Hufflepuff, too much of a cold heart for that. Enough bravery for Gryffindor, enough wit for Ravenclaw but a lot of talent" The hat pondered. Sherlock quirked an eyebrow. Cold heart? Well he supposed it ran in the Holmes family since they were all sociopaths.

"Slytherin!" The hat exclaimed after a few moments of thought. Sherlock smirked as the Slytherin table began cheering and hoped off the stool. He caught John's eye from the Gryffindor table and smiled at him. He walked towards the table and found Malfoy had cleared a seat next to him. Right then, time to pretend to be sociable. Sherlock huffed and sat down next to Malfoy. He caught Mycroft's approving nod.

"Let the feast... begin" Dumbledore announced as food appeared on the table. There was anything one could ever dream of on the table. He watched with the slightest distaste as everything began stuffing their faces except, of course, Mycroft who smiled smugly at everyone.

"Sherlock, that's Jim and this is Irene" Malfoy said after he had eaten half of his plate. Sherlock glanced at the two Malfoy had gestured to and observed them. Jim was pale, beady eyed and had a maniacal look about him. Sherlock guessed Jim was in his second or possibly third year since he already had his Slytherin tie. Irene was just smiling seductively at Sherlock with her red tainted lips.

"Nice to meet you" Sherlock forced the words out of his mouth.

"You too" Jim said. He was Irish. Sherlock was about to take some mashed potatoes before a grey head popped out of them. Normally he wasn't scared, he just never had ghosts popping out of salads before.

"It's the Bloody Baron!" Jim exclaimed. The ghost rose to his full height just as more ghosts began gliding out of the walls and drifting through the hall. No one payed them much attention, everyone was mostly focused on the food.

"Welcome to Slytherin" The ghost called before drifting off down the table.

Sherlock was in his Mind Palace throughout the whole dinner. He had resorted to filing away information about the school and the out of bounds 3rd floor when the food disappeared from the tables. The prefects stood up just as the students did. Mycroft and a brown haired girl led the Slytherins off to the dungeons. Sherlock managed to find John before he had disppeared in the sea of students.

"Check your timetable. If we have classes together, I've got something to discuss with you" He told John before running off after the Slytherins. He ran down the stairs and found Malfoy waiting for him at the bottom.

"Knew you would stray from the group" Malfoy chimed as he led Sherlock down the old corridor. The torches were blazing greens, the banners that hung on the wall were green and silver with the symbol of Slytherin. There were old armors here and there. Sherlock took in everything as they walked into the Common Room. The furniture was black but the decor was green and silver. There were two black, leather sofas with green pillows facing each other in front of a blazing fire. The fire was, just like the torches, green. Each wall had an arch over it and the archetecture around the room was Gothic style. The green blazing on the black bricks made the place even creepier.

"Boy's dormitories to your left, girl's dormitories to your right" Mycroft explained. He and the brown haired girl stayed back as the first years went to their proper dormitories.

"Sherlock" Mycroft called but Sherlock ignored him. He wasn't in the mood for being lectured so he just followed Malfoy to their dormitory.

"That's your brother?" Malfoy asked as they walked through the door into their dormitory.

"Yes. He's a git" Sherlock stated as they passed a small corridor until they reached their proper room. The whole room was quite big, with their trunks beside each four poster bed and in the center of the room 4 dark green bean bag chairs. The drapes around the beds are dark green as well. Since they were in the dungeons, there was only one window in the room and it was like a glass wall between Sherlock and Malfoy's beds. The window was about 5 feet above the ground but you could see the outline of the forest through the dark mist. There were two other boys already settling in for bed.

"Vincent Crabbe and Gregory Goyle" Malfoy said as he made his way towards his own dark wooded, four poster bed. Sherlock narrowed his eyes as he analyzed them. It's like someone had written _IDIOT_ all over their faces when they were born. Sherlock shook his head to clear it from his obviously incompetent roommates and settled down for bed.

But he couldn't sleep. Or maybe it was just Crabbe and Goyle snoring. Usually, Sherlock didn't sleep at all but he felt obligated since it was the first day of term tomorrow. He wasn't worried about the classes, he just wanted to get the night over with so he can go and investigate the 3rd floor with John! So Sherlock quietly slipped out of bed and padded towards the window. The half crescent moon was filling the room with a silver glow. He sat down on the cold floor and rested his forehead on the equally cold glass. Suddenly, a ball of black fury jumped into his lap. It took him less than a second to realized Thanatos had managed to crawl out of his cage. Again. Sherlock scratched the kitten behind the ears. He didn't like sleeping either. In all honesty, Sherlock believed sleeping was a waste of time. Why sleep when he could be doing something of importance?

"Sherlock, you alright mate?" He heard Malfoy ask quietly. Sherlock turned and glanced at Malfoy who was sitting in bed looking at him with slight concern in the darkness.

"What? Yeah I'm fine" Sherlock said, turning back to the window and petting Thanatos who had curled up in his lap.

"You've been sitting there for 2 hours and you haven't moved" Malfoy pointed out. Has it really been 2 hours since he sat down? Time travels quickly when he's thinking.

"I was just thinking" Sherlock mumbled.

"About what?" Malfoy asked.

"The restricted corridor" Sherlock explained. Malfoy cocked an eyebrow in question before standing up and sitting across from Sherlock on the cold floor.

"Why would you care about the restricted corridor. It's restricted so we can't go there anyways" Malfoy said.

"I don't know it just seems... suspicious. Why would they only restrict _one_ corridor?" Sherlock pondered aloud. He watched as Thanatos scampered off his lap and snuggled up to Malfoy.

"Is this your cat?" Malfoy asked, petting the coal black kitten.

"Yep. That's Thanatos" Sherlock said. Malfoy smiled as the kitten purred but his smile faded as the cat tried to bite him. Sherlock began explaining the theories that he had deduced while Malfoy listened intently, offering his knowledge on the 3rd floor from eavesdropping on Snape. Sherlock was quite surprised when Malfoy didn't insult him for his deductions, he actually found them amazing, just like John. Maybe Sherlock would be able to make some friends here? He didn't dwell on that thought for long because, who would want to be friends with Sherlock Holmes?


End file.
